Catalyst compositions for selective dimerization of ethylene

ABSTRACT

A catalyst composition, including a titanate of the formula Ti(OR) 4  wherein each R is the same or different, and is a hydrocarbon residue; a catalyst additive, wherein the catalyst additive is a dibutyl ether a silicate, a silazane, an aromatic ether, a fluorocarbon, or a combination comprising at least one of the foregoing; and an organic aluminium compound.

This application is a National Stage application of PCT/IB2014/066863,filed Dec. 12, 2014, which claims the benefit of U.S. ProvisionalApplication No. 61/915,764, filed Dec. 13, 2013 and U.S. ProvisionalApplication No. 61/916,549, filed Dec. 16, 2013, both of which areincorporated by reference in their entirety herein.

FIELD

Disclosed herein are catalyst systems and processes for the dimerizationof alkenes to prepare α-olefins, in particular catalyst systems andprocesses for the dimerization of ethylene to prepare 1-butene ordownstream products thereof.

BACKGROUND

Alpha-olefins such as butene are desirable substances in the chemicalindustry. Due to the presence of the terminal double bond, they can beconverted into a number of other valuable compounds. For example, butenecan be converted to compounds such as butanol, butadiene, and butanone.In polymerisation reactions it can be used as monomer or co-monomer andis particularly valuable in the production of plastics. For example, itcan be used as a co-monomer with ethylene for the production of highstrength and high stress crack resistant polyethylenes. One route to thepreparation of butene is the cracking of higher petrochemical fractionscontaining more than 4 carbon atoms. Another route to the preparation ofbutene, which has for a long time been the subject of intense research,is via the dimerization of ethylene (ethene). An aim of the catalyticdimerization of ethylene into 1-butene was producing higher chainpolymers via the growth reaction of the organoaluminum compounds. Theindustrial synthesis of 1-butene can be achieved using nickel ortitanium catalysts such as Alphabutol™ (Handbook of PetroleumProcessing, Edited by D. S. J. Jones, P. R. Pujadó; Springer Science2008; Forestière et al., Oil & Gas Science and Technology—Rev. IFP(2009);64(6):649-667). The Alphabutol™ process is also known as BUCAT.The catalytic activity of Alphabutol™ can be low, at roughly 1 kg ofproduct per gram of titanium. Polymer formation and lengthy initialinduction period are major drawbacks for the commercial Alphabutol™system.

Thus, a demand still remains in the art for improved processes for thepreparation of α-olefins such as butene from alkenes such as ethene,especially for processes with one or more of long catalyst lifetimes,high specificity, short initiation times (induction periods), andreduced polymer formation.

SUMMARY

A catalyst composition comprises a titanate of the formula Ti(OR)₄wherein each R is the same or different, and is a hydrocarbon residue; acatalyst additive, wherein the catalyst additive is a dibutyl ether, asilicate, a silazane, an aromatic ether, a fluorocarbon, or acombination comprising at least one of the foregoing; and an organicaluminium compound.

A process for the preparation of the catalyst composition comprisespre-treating the titanate and the catalyst additive with an inertsolvent, preferably hexane; and combining the pre-treated titanate andcatalyst additive with the organic aluminum compound.

A reaction process for the preparation of an α-olefin, comprisescontacting an alkene with the above catalyst composition underconditions effective to form the α-olefin.

A process for the preparation of a downstream product comprises reactingthe α-olefin of any one or more of claims 1 to 10, or the α-olefinprepared according to any one or more of claims 11 to 14, to provide thedownstream product, preferably wherein the downstream product is ahomopolymer or copolymer comprising units derived from the α-olefin.

BRIEF DESCRIPTION OF THE DRAWINGS

The following Figures are intended for illustration only and are not tobe considered as limiting the scope.

FIG. 1 represents a schematic process for producing olefin in accordancewith one example of the presently disclosed subject matter.

FIG. 2 represents a schematic process for producing olefin in accordancewith one example of the presently disclosed subject matter.

FIG. 3 represents two forms of triethylaluminum.

FIG. 4 illustrates an “Aufbaureaktion” or ring opening reaction.

FIG. 5 illustrates the relationship of catalytic activity with Al/Timolar ratio.

FIG. 6 illustrates the relationship of polymer formation with Al/Timolar ratio.

FIG. 7 illustrates the solvent effect on catalytic activity.

DETAILED DESCRIPTION

The present invention is generally based on the object of overcoming atleast one of the problems encountered in the state of the art inrelation to the dimerization reaction of an alkene, preferably ethene,to give an α-olefin, preferably 1-butene, or downstream products derivedtherefrom, preferably polymers.

In some embodiments, the present invention is further based on theobject of providing a catalyst system and a process for a reaction thathas one or more, preferably all, of a high product specificity, reducedpolymer fouling, and a high catalyst lifetime.

In some embodiments, the present invention is based on the object ofproviding a catalyst system and a process for a reaction which has ashort initiation time.

Another object is to provide an efficient and sustainable α-olefinsource for producing downstream products and shaped bodies.

A contribution to achieving at least one of the above-mentioned objectsis made by a catalyst composition comprising the following catalystcomponents:

a. a titanate of formula Ti(OR)₄ wherein each R is the same or differentand is a hydrocarbon residue, preferably an alkyl group or an arylgroup, more preferably an alkyl group;

b. a catalyst additive, wherein the catalyst additive is a dibutylether, a silicate, a silazane, an aromatic ether, a fluorocarbon, or acombination comprising at least one of the foregoing; and

c. an organic aluminium compound.

Another contribution to achieving at least one of the above-mentionedobjects is made by a catalyst composition comprising the followingcatalyst components:

a. a titanate with the general formula Ti(OR)₄, wherein R is ahydrocarbon residue and each R can be the same as or different to theother R in the molecule;

b. an organic aluminium compound; and

c. a hydrocarbon,

wherein the catalyst components are dissolved in the hydrocarbon c.; andwherein the molar ratio of the amount of aluminium compound b. to thetotal amount of alkene is greater than one. A catalyst additive asdescribed above or a catalyst modifier may be present in thisembodiment, where the catalyst additive may be a dibutyl ether, asilicate, a silazane, an aromatic ether, a fluorocarbon, or acombination comprising at least one of the foregoing; or an amine orether catalyst modifier distinct from the dibutyl ether or the aromaticether as further described below; or a combination comprising at leastone of the foregoing.

Another contribution to achieving at least one of the above mentionedobjects, is made by a process for the preparation of a catalystcomposition comprising the following preparation steps:

a. providing a hydrocarbon;

b. introducing a titanate with the general formula Ti(OR)₄, wherein R isa hydrocarbon residue and each R can be the same as or different to theother R in the molecule, into the hydrocarbon; and

c. introducing an aluminium compound into the hydrocarbon,

wherein not more than 0.1% alkene is present in the catalyst compositionduring any of the steps a, b, or c. In some embodiment the processfurther comprises a cooling step. Another aspect is a catalystcomposition obtainable by this process. In this embodiment, a preferredcatalyst composition comprises the following:

a. a tetraalkyl titanate, preferably tetra-n-butyl titanate;

b. an ether catalyst modifier, preferably tetrahydrofuran;

c. a trialkyl aluminium compound, preferably triethyl aluminium; and

d. an alkane, preferably hexane.

Preferred titanates are compounds of the general formula Ti(OR)₄,wherein R stands for a hydrocarbon residue, preferably an alkyl group oran aryl group, more preferably an alkyl group, and each R in a moleculemay be the same as or different to the other R groups in the molecule.Titanates are known to the skilled person, and the specific titanate maybe selected in order to enhance the advantageous properties of theprocess. R is preferably a straight chain or branched alkyl group, morepreferably straight chain. R is preferably a C₂-C₁₂ alkyl group, morepreferably a C₂-C₈ alkyl group, most preferably a C₃-C₅ alkyl group. Thepreferred alkyl group is butyl, which includes n-butyl and iso-butyl.Suitable organic titanium compounds include, but are not limited to,tetraethyl titanate, tetraisopropyl titanate, titanium tetra-n-butoxide(TNBT), and tetra-2-ethylhexyl titanate. In one embodiment, the organictitanium compound is titanium tetra-n-butoxide.

In some embodiments, the titanate can be present in high concentrationin the reaction mixture, for example in a concentration of about 0.0001to about 0.1 mol/dm³, about 0.0002 to about 0.01 mol/dm³, morepreferably about 0.0005 to about 0.001 mol/dm³.

The organic aluminum compound is usually compounds of the formula AlR₃,wherein R stands for a hydrocarbon, hydrogen or a halogen, preferably ahydrocarbon or a halogen, more preferably alkyl or aryl or halogen, mostpreferably an alkyl group or halogen and each R in a molecule may be thesame as or different to the other R groups in the molecule. Aluminiumcompounds are known to the skilled person, wherein specific aluminiumcompounds are selected in order to enhance the advantageous propertiesof the process. R is preferably a straight chain or branched alkylgroup, more preferably straight chain. R is preferably a C₁-C₁₂ alkylgroup, more preferably a C₁-C₈ alkyl group, most preferably a C₁-C₄alkyl group. The preferred alkyl group is ethyl. Suitable organicaluminum compounds include, but are not limited to, triethylaluminum(TEAL), tripropylaluminum, triisobutylaluminum, diisobutylaluminumhydride, and trihexylaluminum. In one embodiment, the organic aluminumcompound is triethylaluminum.

The molar ratio of Al:Ti of the catalyst composition can impact thecatalytic activity of the catalyst composition. In one example, thecatalytic activity can be enhanced when the Al:Ti molar ratio isincreased, as shown in Example 1. In addition, when the catalystcomposition is used for producing 1-butene via catalytic dimerization ofethylene, the Al:Ti molar ratio can impact the polymer (e.g.,polyethylene) formation during the production process, as shown inExample 1. In one example, increased Al:Ti molar ratio can lead tohigher polymer formation. The Al:Ti molar ratio of the catalystcomposition can range from about 1:1 to about 40:1, from about 1: toabout 30:1, from about 1:1 to about 20:1, from about 1:1 to about 10:1,from about 1:1 to about 6:1, from about 1:1 to about 5:1, from about 1:1to about 4:1, from about 1:1 to about 3:1, from about 1:1 to about 2:1,from about 2:1 to about 5:1, from about 2:1 to about 3:1, from about 3:1to about 4,:1 or from about 4:1 to about 5:1 In certain embodiments, theAl:Ti molar ratio of the catalyst composition is from about 1: to about5:1. The polymer formation can be avoided when the Al:Ti molar ratio isabout 5:1 or less, as shown in Example 1. In some embodiments, the Al:Timolar ratio of the catalyst composition is about 5:1. In someembodiments, the Al:Ti molar ratio of the catalyst composition is about3:1. In other embodiments, the Al:Ti molar ratio of the catalystcomposition is about 2:1.

The catalyst additive may be a dibutyl ether, a silicate, a silazane, anaromatic ether, a fluorocarbon, or a combination comprising at least oneof the foregoing. As used herein the term “catalyst additive” is usedfor convenience to refer to one or more of the foregoing compounds, andis not intended to imply any particular functional or mechanisticproperties of the compounds.

In some embodiments, the catalyst additive comprises dibutyl ether,specifically di-n-butyl ether, di-iso-butyl ether, or a combinationcomprising at least one of the foregoing.

In some embodiments the catalyst additive comprises a silicate, wherethe silicate has the formula SiR_(y)(OR)_(4-y), wherein y is 0 to 3,preferably wherein y is 0, and each R is the same or different and ishydrogen or a C₁₋₁₂ hydrocarbon residue, preferably C₁-C₆ alkyl group,provided that R is not hydrogen when it is directly bonded to silicon.

In some embodiments the silicate has the general formula Si(OR)₄ orSiR_(x)(OR)_(4-x) with x=1, 2 or 3, wherein R stands for a hydrocarbonresidue or H, preferably an alkyl group or an aryl group, mostpreferably an alkyl group; and each R in the molecule may be the same asor different to the other R in the molecule. In some embodiments of thecatalyst composition, at least one R group of the silicate is a C₁-C₁₂alkyl group, preferably a C₁-C₆ alkyl group, more preferably a C₁-C₃alkyl group. In an aspect of this embodiment, all of the R groups in thesilicate are alkyl groups, the same as or different to each other, inthe range C₁-C₁₂, preferably in the range C₁-C₆, more preferably in therange C₁-C₃. In preferred embodiments of the catalyst composition, thesilicate is Si(OEth)₄, that is, Si(OCH₂CH₃)₄.

In some embodiments, the silicate has the general formula Si(OR)₄. In anaspect of this embodiment, the silicate is Si(OC₂H₅)₄.

In some embodiments, the silicate has the general formulaSiR_(x)(OR)_(4-x). In the aspects of this embodiment, the silicate hasthe formula SiR(OR)₃, SiR₂(OR)₂, SiR₃(OR). In an aspect of thisinvention, all R in the silicate are ethyl, the silicate having aformula selected from the group consisting of the following:Si(C₂H₅)(OC₂H₅)₃, Si(C₂H₅)₂(OC₂H₅)₂, and Si(C₂H₅)₃(OC₂H₅).

In some embodiments the catalyst additive comprises a silazane.Preferred silazanes have the general formula (SiR₃)NH(SiR₃), wherein Ris a hydrocarbon, H, or a halogen, and each R may be the same as ordifferent to the other R in the molecule. Preferred hydrocarbons R inthis context are methyl, ethyl, propyl, butyl, phenyl, toluyl, orcyclohexyl, preferably methyl. Preferred halogens in this context are F,Cl, Br, or I, preferably Cl or F, preferably F. In some embodiments, thecatalyst composition comprises (Si(CH₃)₃)₂NH.

In some embodiments the catalyst additive comprises an aromatic ether ofthe formula R¹OR², wherein each R¹ is a hydrocarbon residue and R² is anaromatic hydrocarbon residue, preferably wherein each R¹ and R² is thesame or different substituted or unsubstituted C₆₋₁₅ aromatic group,more preferably wherein each R¹ and R² is the same substituted orunsubstituted C₆₋₁₀ aromatic group, most preferably wherein each R¹ andR² is phenyl. Preferred aromatic ethers comprising an aromatichydrocarbon are methyl phenyl ether, ethyl phenyl ether, propyl phenylether, butyl phenyl ether, cyclohexyl phenyl ether, and preferablydiphenyl ether.

In some embodiments the catalyst additive comprises a fluorohydrocarbon. In some embodiments preferred fluoro hydrocarbons in thiscontext are mono-di- tri- or tetra-fluorinated hydrocarbons, based onmethane, ethane, propane, butane, benzene, toluene, naphthalene, orxylene, preferably based on benzene. In some embodiments the fluorohydrocarbon is a fluorinated C₁₋₁₅ hydrocarbon, preferably a fluorinatedC₆-₁₂ aromatic hydrocarbon, more preferably fluorobenzene. Thefluorinated C₁-₁₅ hydrocarbon may be mono- di- tri- ortetra-fluorinated, or have more fluorine substituents, and may beperfluorinated.

In some embodiments, it is preferred for the catalyst composition tocomprise a catalyst modifier, in particular an amine catalyst modifieror an ether catalyst modifier that is distinct from the dibutyl etherand the aromatic ether.

Such ether catalyst modifiers are known, and can act as a co-catalyst orcatalyst modifiers to the titanate, preferably by coordination of thetitanate with a lone pair of electrons. Such ether catalyst modifiersare well known to the skilled person and he may select any ether whichhe considers to be appropriate in the context and preferably improvingthe favourable characteristics of the reaction, preferably a reducedinitiation time, increased yield and reduced polymer fouling.

Preferred ether catalyst modifiers may be monoethers or polyethers.Preferred substituents of the ether are alkyl groups. Preferred alkylgroups are methyl, ethyl, propyl, n-butyl, iso-butyl, t-butyl, and otherhigher alkyl groups. Some preferred monoether catalyst modifiers aredimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, methylethyl ether, methyl propyl ether, methyl butyl ether, ethyl propylether, ethyl butyl ether, propyl butyl ether, tetrahydrofuran, ordihydropyran. The preferred mono ether is tetrahydrofuran.

Preferred polyether catalyst modifiers are 1,4 dioxane or ethers basedon polyalcohols, preferably glycols or glycerols, preferably ethyleneglycol. Preferred ethers based on glycol are dimethyl ethylene glycol,diethyl ethylene glycol, dipropyl ethylene glycol, dibutyl ethyleneglycol, methyl ethyl ethylene glycol, methyl propyl ethylene glycol,methyl butyl ethylene glycol, ethyl propyl ethylene glycol, ethyl butylethylene glycol, propyl butyl ethylene glycol.

In some embodiments, the catalyst composition contains the dibutyl ethermodifier or the aromatic ether modifier and one further ether catalystmodifier distinct from the dibutyl ether and the aromatic ether,preferably an ether as described above, more preferably tetrahydrofuran.

In another embodiment, the catalyst composition contains the butyl ethermodifier two or more further ether catalyst modifiers distinct from thedibutyl ether and the aromatic ether, preferably with at least one ormore, preferably all, as described above, preferably with one of theethers being tetrahydrofuran.

In some embodiments the catalyst additive and the further ether catalystmodifier are present in a molar ratio in the range of about 1:5 to about5:1, preferably in the range from about 1:3 to about 3:1, morepreferably in the range from about 1:2 to about 2:1. In an aspect ofthis embodiment, the dibutyl ether and the further ether catalystmodifier are present in the catalyst composition in a molar ratio in therange of about 1:5 to about 5:1., preferably in the range from about 1:3to about 3:1, more preferably in the range from about 1:2 to about 2:1.

As previously stated, in some embodiments a dibutyl ether, a silicate, asilazane, an aromatic ether, or a fluorocarbon catalyst additive is notpresent. In these embodiments the amine or ether catalyst modifierdistinct from the dibutyl ether and the aromatic ether as describedabove can be present, however. In an embodiment an ether catalystmodifier is present, and tetrahydrofuran is preferred. In anotherembodiment, the catalyst composition contains at least two or more ethercatalyst modifiers, preferably with at least one or more, preferablyall, as described above, preferably with one of the ethers beingtetrahydrofuran.

The skilled person may modify the relative ratios of the components ofthe catalyst composition in order to increase the advantageousproperties of the reaction.

The catalyst compositions catalyse the reaction of an alkene, preferablyethene, to obtain an α-olefin, preferably 1-butene. It is preferred thatthe catalyst composition contribute to favourable properties of thereaction, preferably to improved catalyst activity, product selectivityof α-olefin and reduction of undesired polymer fouling. Preferredcatalyst compositions comprise a tetra(C₁₋₄)alkyl titanate, morepreferably a tetra-n-butyl titanate; a catalyst additive that can bedibutyl ether, a combination of dibutyl ether and tetrahydrofuran, asilicate, a fluoro hydrocarbon, an aromatic ether, a silazane; andtriethyl aluminium. Other preferred catalyst compositions comprise atetra(C₁₋₄)alkyl titanate, more preferably a tetra-n-butyl titanate;optionally, an ether catalyst modifier, preferably tetrahydrofuran, aninert hydrocarbon, preferably hexane; and triethyl aluminium.

The catalyst composition may be present dissolved in a liquid,preferably an alkane, preferably hexane, preferably as a homogeneousliquid. In an aspect of this embodiment, the liquid is an alkane or analkene or an aromatic solvent. In a further aspect of this embodiment,the liquid is a C₄-C₁₂ alkane, preferably a C₄-C₈, more preferably aC₄-C₆ alkane; or a C₄-C₁₂ alkene, preferably a C₄-C₈ alkene, morepreferably a C₄-C₆ alkene. In a further aspect of this embodiment, theliquid is one or more selected from the group consisting of butene,hexane, heptane, and octane.

The catalyst composition may be pre-prepared or prepared in situ, andpreferably is pre-prepared.

When prepared in situ, the components of the catalyst composition areintroduced to the reaction system as two or more components that areadded sequentially.

In some embodiments, the titanate is pre-mixed with an ether catalystmodifier, optionally together with the catalyst additive. In an aspectof this embodiment, they are mixed in an inert solvent, preferably analkane, preferably one or more of the following: pentane, hexane,heptane, octane, nonane, or decane, preferably hexane.

In some embodiments, the titanate, the ether catalyst modifier, optionalcatalyst additive, or a combination thereof, and the organic aluminiumcompound are premixed, preferably in the absence of an olefin (alkene).In an aspect of this embodiment, they are mixed in an inert solvent,preferably an alkane, preferably one or more of pentane, hexane,heptane, octane, nonane, or decane, preferably hexane.

It was found that certain solvents (e.g., olefins) can render theorganic aluminum compound unavailable from activating the organiccompound of titanium. In addition, certain solvents (e.g., olefins) canlead to increased induction period. The presently disclosed processes ofmaking the catalyst compositions include pre-treating the organictitanium compound with an inert solvent, and adding the organic aluminumcompound to the mixture of the organic titanium compound and the inertsolvent to activate the organic titanium compound in the presence of theinert solvent. Furthermore, the organic titanium compound can bedissolved in or mixed with an ether prior to or concurrently at theinert solvent pre-treating procedure. In one embodiment, the catalystcan be mixed with the ether prior to the inert solvent pre-treating.Thus, in some embodiments, the titanate is pre-mixed with a catalystmodifier, preferably an ether catalyst modifier, preferablytetrahydrofuran. In an aspect of this embodiment, they are mixed in aninert solvent, preferably an alkane, preferably one or more selectedfrom the group consisting of the following: pentane, hexane, heptane,octane, nonane, decane, preferably hexane. It has been unexpectedlyfound that this pre-treatment process can result in shortened initiationtimes. The catalyst additive can further be optionally mixed at the sametime as the titanate and the ether catalyst modifier.

Pre-treating the organic titanium compound with an inert solvent (e.g.,n-hexane) can provide a condition for the subsequently added organicaluminum compound to pre-activate the organic titanium compound prior toadding the catalyst composition that includes the organic titaniumcompound and the organic aluminum compound to the solvent, which, aspresented above, can render the organic aluminum compound unavailablefrom activating the organic titanium compound. The pre-activation of theorganic titanium compound can yield a controlled catalyst reaction, andcan also shorten the induction period, as described in Example 2. Oncethe organic titanium compound is activated in the pre-activationprocedure, it can remain active. The pre-treating can be conducted in anitrogen atmosphere.

In accordance with the presently disclosed subject matter, the organicaluminum compound can be TEAL. TEAL can exist in two forms: monomericform (AlEt₃) and dimeric form (Al₂Et₆), where Et is ethyl, CH₂CH₃, asshown in FIG. 3. In the presence of the ether that dissolves thecatalyst (e.g., THF), TEAL remains in the monomeric form. The catalyticactivity of TEAL accelerates when it exists in the monomeric form.Therefore, in the presence of the ether that dissolves the catalyst(e.g., THF), TEAL exists in the monomeric form that enables it toactivate the catalyst, e.g., TNBT. In the presence of certain solvents,such as olefins (e.g., 1-hexene), TEAL remains in the dimeric form,which renders TEAL unable to activate the catalyst, e.g., TNBT.Furthermore, certain solvents, such as olefins (e.g., 1-hexene) areassociated with other side reactions, for example, the so-called“Aufbaureaktion” or ring opening reactions as described in Delaney et.al., J. Chem. Soc. Perkin Trans (1986); Rosenthal et. al.,Organometallics (2007);26:3000-3004, and as shown in FIG. 4. The“Aufbaureaktion” or ring opening reactions can render the co-catalystand/or catalyst unavailable for important catalyst reduction to theactive form.

In other embodiments, the titanate, the ether catalyst modifier, and thealuminium compound are premixed, preferably in the absence of olefin. Inone aspect of this embodiment, they are mixed in an inert solvent,preferably an alkane, preferably one or more selected from the groupconsisting of the following: pentane, hexane, heptane, octane, nonane,decane, preferably hexane. The catalyst additive can further beoptionally mixed at the same time with these components in the inertsolvent.

In some embodiments, the preparation of the catalyst compositioncomprises the following steps:

1. First, the titanate, preferably the titanate and ether catalystmodifier, are premixed in an inert solvent, preferably an alkane,preferably one or more selected from the group consisting of thefollowing: pentane, hexane, heptane, octane, nonane, decane, preferablyhexane.

2. Second, the aluminium compound is introduced into the inert solvent.

In some embodiments, no more than 10% of alkene is present in thepreparation of the catalyst compositions. Preferably, no alkene ispresent in any of the steps of the catalyst preparation. The catalystcomposition first comes into contact with alkene during the reaction forthe preparation of the α-olefin. In some embodiments, no polymer ispresent or created in the catalyst composition during its preparation.

In some embodiments, the catalyst composition is prepared shortly beforeuse in the preparation of an α-olefin. It is preferred for the preparedcatalyst system not be stored for longer than 1 week, preferably notlonger than 1 day, more preferably not longer than 5 hours before beingemployed as catalyst for the preparation of an α-olefin or otherreaction process.

In some embodiments, the catalyst composition is not activated untilshortly before being employed in the reaction. It is preferred that theorganic aluminium compound not be brought into contact with the othercatalyst components earlier than 30 minutes, preferably not earlier than15 minutes, more preferably not earlier than 10 minutes, most preferablynot earlier than 5 minutes before the catalyst composition is employedin the reaction.

In some embodiments it is preferred for the individual components to beprepared shortly before use. It is preferred that at least one or moreof the catalyst components not be stored for longer than 1 week,preferably not longer than 1 day, more preferably not longer than 5hours after its preparation and before being employed as a component ofthe catalyst for the reaction. In an aspect of this embodiment, thetitanate is not stored for longer than 1 week, preferably not longerthan 1 day, more preferably not longer than 5 hours after itspreparation and before being employed as a component of the catalyst inthe reaction. In an aspect of this embodiment, the organic aluminiumcompound is not stored for longer than 1 week, preferably not longerthan 1 day, more preferably not longer than 5 hours after itspreparation and before being employed as a component of the catalyst forthe reaction.

A contribution to achieving at least one of the above mentioned objectsis made by a reaction process for the preparation of an α-olefin from analkene, preferably a reaction process for preparation of a C₄-C₂₀α-olefin from a C₂-C₈ alkene, most preferably a process for preparationof 1-butene from ethene. In some embodiments of a process for thepreparation of the α-olefin, an alkene, preferably a C₂-C₈ alkene, mostpreferably ethene, comes into contact with a catalyst composition asdescribed above. The α-olefin includes at least 2 repeat units based onthe alkene. The alkene and the catalyst may come into contact in ahomogeneous liquid phase.

In some embodiments, the reaction is carried out as a flow reaction. Inother embodiments, the reaction is carried out as a batch reaction. Itis preferred that the reaction proceed as a homogeneous liquid phasereaction.

FIG. 1 shows a schematic process diagram 100 for an example batchreaction process. In the first step 101 the catalyst is prepared. In thenext or second step 102 the catalyst and olefin, preferably ethene, arebrought into contact in the liquid phase, preferably in 1-butene as asolvent. In the subsequent or third step 103 the α-olefin product of thereaction, preferably 1-butene, is separated from the product mix.Optionally, the catalyst can be salvaged from the product mix. Thecatalyst can thus be recycled.

FIG. 2 shows a schematic process diagram 200 for an example flowreaction process. In the first step 201 the catalyst is prepared andintroduced into the reaction system, preferably a 1-butene solventsystem. The catalyst components can either be premixed or addedsequentially. In the second step 202 the alkene, preferably ethene, isintroduced into the reaction system. In the third step 203 the α-olefinproduct, preferably 1-butene, is removed from the reaction system.

The skilled person can select the solvent for the reaction process inorder to improve the advantageous properties of the reaction. Thesolvent for the reaction is preferably an alkane, an alkene, or anaromatic hydrocarbon. Preferred alkanes in this context are C₂-C₁₂alkanes, preferably C₄-C₈ alkanes, most preferably hexane, heptane, oroctane, including all isomers of each, and more preferably n-hexane.Preferred alkenes in this context are C₂-C₁₂ alkenes, preferably C₄-C₈alkenes, including all isomers of each, most preferably butene.Preferred aromatic hydrocarbons in this context are benzene, toluene,and phenol.

In some embodiments, the preferred solvent for the reaction is the sameas the α-olefin product, preferably 1-butene. In other embodiments, thesolvent for the reaction is different than the solvent employed forpreparation of the catalyst system.

The reaction can be performed at a temperature of from about 20° C. toabout 150° C., from about 40° C. to about 100° C., from about 20° C. toabout 70° C., from about 50° C. to about 70° C., from about 50° C. toabout 55° C., or from about 55° C. to about 65° C. In one embodiment,the reaction is performed at a temperature of about 60° C. The reactioncan be performed at a pressure of from about 5 bars to about 50 bars,from about 10 bars to about 40 bars, or from about 15 bars to about 30bars. In some embodiments, it is preferred that at least one of thefollowing conditions be satisfied during the reaction:

a. the pressure of the system is about 1 to about 50 bar, preferablyabout 5 to about 50 bar, more preferably about 10 to about 40 bar, mostpreferably in the range from about 15 to about 30 bar; or

b. the temperature of the system is about 30 to about 150° C.,preferably about 40 to about 100° C., more preferably about 50 to about70° C., most preferably about 55 to about 65° C.

In some embodiments, the reaction is conducted in a batch where aselected volume of the presently disclosed catalyst composition can beintroduced into a reactor provided with usual stirring and coolingsystems, and can be subjected therein to an ethylene pressure, which canbe from about 22 bars to about 27 bars. In some embodiments, thereaction using the presently disclosed catalyst composition is conductedat an ethylene pressure of about 23 bars. One of ordinary skill in theart can adjust the temperature, pressure and other conditions of thereaction in order to bring about favorable properties of the reaction,for example, in order to ensure that the reaction system is present as ahomogeneous liquid phase.

The above conditions are particularly preferred where the solvent forthe reaction is 1-butene, in order to ensure that the reaction system ispresent as a homogeneous liquid phase. Where other solvents are used,the skilled person may adjust the temperature, pressure and otherconditions of the reaction in order to bring about favourable propertiesof the reaction and in order to ensure that the reaction system ispresent as a homogeneous liquid phase. In some embodiments of theprocess, the alkene and the catalyst come into contact in a liquid phasecomprising at least 50 wt. % but-1-ene, based on the total weight of theliquid phase.

The reaction product may be extracted by any method which the skilledperson considers to suitable in the context. Preferred methods ofextraction include distillation, precipitation, crystallisation,membrane permeation, and the like.

In some embodiments, the reaction process for the preparation of anα-olefin is coupled to an further subsequent reaction in order to obtaina downstream product. Thus, a process for the preparation of adownstream product may comprise the following preparation steps:

i. preparation of an α-olefin by a process according to the invention;and

ii. reaction of the α-olefin to obtain the downstream product, forexample a polymer.

Preferred downstream products are those obtained from polymerisationreactions, hydrogenation reactions, halogenation reactions, and otherchemical functionalization reactions, preferably polymerisationreactions. Preferred monomeric downstream products are chlorobutene,butadiene, butanol, and butanone. Preferred functionalization productsare aromatic or non-aromatic compounds, saturated or unsaturatedcompounds, ketones, aldehydes, esters, amides, amines, carboxylic acids,alcohols, and the like.

In some aspects, the polymer is a poly α-olefin or copolymer comprisingat least one α-olefin as a co-monomer. Preferred polymerisationreactions can be mono-polymerization (i.e., homopolymerisation)reactions or copolymerization reactions, preferably copolymerizationreactions. The preferred homopolymerisation product is polybutene. Thepreferred co-polymers comprise units derived from the α-olefin,preferably 1-butene, and one or more co-monomers such as ethene,propene, pentene, styrene, acrylic acid, methacrylic acid, methylacrylate, methyl methacrylate, acrylonitrile, methacrylonitrile, orvinyl chloride, preferably ethene. The preferred copolymer is acopolymer of ethene and 1-butene, preferably with a larger weightpercent (wt. %) of units derived from ethene monomers than of unitsderived from 1-butene monomers, preferably with a weight ratio of etheneunits to 1-butene units of about 50:1 to about 5:1, more preferablyabout 30:1 to about 10:1, most preferably about 25:1 to about 15:1. Theskilled person may vary the ratio relating the mass of ethene monomersand 1-butene monomers in order to achieve the desired properties of thecopolymers, such as crystallinity and elasticity.

In some embodiments of the process for the preparation of a downstreamproduct, the product contains compounds with chain lengths inproportions determined by or approximating to the Anderson Schulz Florydistribution.

In some embodiments, the downstream products are further connected toyield fatty acids, preferably with chain lengths in proportionsdetermined by or approximating to the Anderson Schulz Florydistribution.

In some embodiments, the downstream products are further processed,particularly in the case where the downstream product is a polymer,particularly when it is a polybutene homopolymer or copolymer. In anaspect of this embodiment, this further processing preferably involvesformation of shaped objects such as plastic parts for electronicdevices, automobile parts, such as bumpers, dashboards, or other bodyparts, furniture, or other parts or merchandise, or for packaging, suchas plastic bags, film, or containers.

The following examples are illustrative of the presently disclosedsubject matter and they should not be considered as limiting the scopeof the subject matter or claims.

EXAMPLES

The following test methods are applicable to the claims, and were usedin the Examples.

Polymer fouling was identified by visual inspection and by using a metalspatula to scrape the inside surfaces of the reactor followingcompletion of the reaction. Where polymer fouling occurs, a thin layerof polymer can be seen on the surfaces of the walls of the reactorand/or on the stirrer. The thin polymer layer is white is colour andincludes thin strands.

Initiation time was determined by monitoring the pressure in the reactoror the flow rate of the feed to the reactor. Once the reaction starts,ethene feed is consumed.

In a batch reactor, onset of reaction is manifested as a drop inabsolute pressure. Thus, pressure remains roughly constant during theinitiation period and starts to drop once the initiation period is over.The initiation time is the time spent at roughly constant pressure oncethe reactants and catalyst have been brought into contact and before thereaction starts.

In a continuous reactor, onset of reaction is manifest as an increase inthe flow rate of ethene entering the reactor. At constant pressure,there is roughly no flow of ethene into the reactor during theinitiation period. Ethene flows into the reactor once the initiationperiod is over. The initiation time is the time spent at roughly zeroflow rate once the reactants and catalyst have been brought into contactand before the reaction starts.

Example 1

Example 1 illustrates the catalyst system including a tetra-substitutedtitanate, a dibutyl ether, and trialkyl aluminium, and its use in aprocess for the preparation of an α-olefin from an alkene, in particularpreparation of 1-butene from ethene. The results are summarized in Table1.

Example 1a. The reaction is carried out in a batch reactor (Parr 300 mlAutoclave Model 4566 Mini Benchtop reactor) at 60° C. and 23 bar. Thistemperature and pressure ar maintained in the reactor throughout thereaction. 0.25 ml tetra-n-butyl titanate (Dorf KETAL) and 0.25 mldibutyl ether (Aldrich) are introduced into 50 ml n-hexane (Aldrich). Tothis is added 1.8 ml 1M solution of triethyl aluminium in n-hexane. Thecatalyst system in hexane is introduced into the reactor. The reactionsystem is heated to 60° C. under stirring and pressured to 23 bar withethene for 1 hour. The product is collected in an adjacent vessel afterdepressurising.

Example 1b (comparative). Example 1a is repeated except with 0.25 mltetrahydrofuran in place of 0.25 ml dibutyl ether.

Example 1c. Example 1a is repeated except with a mixture of 0.125 mltetrahydrofuran and 0.125 ml dibutyl ether in place of 0.25 ml dibutylether.

TABLE 1 Dibutyl ether Tetrahydrofuran Example (ml) (ml) Yield Activationtime 1a 0.25 0 High Short 1b 0 0.25 Medium Medium 1c 0.125 0.125 Veryhigh Very short

Example 2

Example 2 illustrates the catalyst system comprising tetraalkyltitanate, a silicate, and trialkyl and its use in a process for thepreparation of an αolefin from an alkene, in particular preparation of1-butene from ethene. The results are summarized in Table 2.

Example 2a. The reaction was carried out in a batch reactor (Parr 300 mlAutoclave Model 4566 Mini Benchtop reactor) at 60° C. and 23 bars. Thistemperature and pressure were maintained in the reactor throughout thereaction. 0.25 ml tetra-n-butyl titanate (Dorf KETAL) and 0.25 mltetraethyl silicate (Aldrich) were introduced into 50 ml n-hexane(Aldrich). To this was added 1.8 ml 1M solution of triethyl aluminium inn-hexane. The catalyst system in hexane was introduced into the reactor.The reaction system was heated to 60° C. under stirring and pressured to23 bar with ethene for 1 hour. The product was collected in an adjacentvessel after depressurising. The yield of 1-butene, expressed as thepercentage based on full conversion of the introduced ethene, was 90%.No polymer fouling was observed.

Example 2b (comparative). Example 2a was repeated except with 9 mltetrahydrofuran in place of 25 ml tetraethyl silicate. The observedyield was <1%. Some polymer fouling was observed.

TABLE 2 Example Co-catalyst Yield Polymer fouling 2a Si(OCH₂CH₃)₄ 90% No2b Tetrahydrofuran <1% Yes

Example 3

Example 3 illustrates the catalyst system comprising a titanate, anether, a methyl aluminoxane, and optionally a second aluminum compound,and its use in a process for the preparation of an polymer from analkene, in particular preparation of polyethylene from ethene.

Example 3a. The reaction was carried out in a batch reactor (Parr 300 mlAutoclave Model 4566 Mini Benchtop reactor) at 60° C. and 23 bar. Thistemperature and pressure were maintained in the reactor throughout thereaction. 0.25 ml tetra-n-butyl titanate (Dorf KETAL) and 0.25 mltetrahydrofuran (Aldrich) were introduced into 50 ml n-hexane (Aldrich).To this was added 1.8 ml 1M solution of methyl aluminoxane in n-heptane(MAO). The catalyst system in hexane was introduced into the reactor.The reaction system was heated to 60° C. under stirring and pressured to23 bar with ethene for 1 hour. The product was collected in an adjacentvessel after depressurising. The yield of polymer, expressed as thepercentage based on full conversion of the introduced ethene, was 95%.

Example 3b. Example 3a was repeated except that 1.8 ml 1M solution ofmodified methyl aluminoxane (CH₃)_(0.7)(iso-But)_(0.3) (MMAO) wasemployed in place of the methyl aluminoxane.

Example 3c. Example 3a was repeated except that a mixture of 0.9 ml 1Msolution of methyl aluminoxane and 0.9 ml 1M triethyl aluminium (TEAL)was employed in place of the methyl aluminoxane.

Example 3d. Example 3a was repeated except that a mixture of 0.9 ml 1Msolution of modified methyl aluminoxane (CH₃)_(0.7)(iso-But)_(0.3) and0.9 ml 1M triethyl aluminium was employed in place of the methylaluminoxane.

Example 3e (Comparative). Example 3a was repeated except that 1.8 ml 1Msolution of triethyl aluminium was employed in place of the methylaluminoxane.

The results are summarized in Table 3, where results are ranked on ascale of 1 to 5, with 1 being the least favourable and 5 being the mostfavourable.

TABLE 3 Example Activator Yield Initiation time Catalyst lifetime 3a MAO2 2 2 3b MMAO 3 3 3 3c MAO and TEAL 4 4 4 3d MMAO and 5 5 5 TEAL 3e TEAL1 1 1

Example 4

Example 4 illustrates the pre-mixed catalyst composition comprising atitanate and an aluminium compound, preferably trialkyl aluminium, andits use in a process for the preparation of an αolefin from an alkene,in particular preparation of 1-butene from ethene.

Example 4a. 50 ml hex-1-ene (from Aldrich) was introduced into a batchreactor (Parr 300 ml Autoclave Model 4566 Mini Benchtop reactor) at 60°C. and 23 bar pressure of ethene. This temperature and pressure weremaintained in the reactor throughout the reaction. 0.25 ml tetra-n-butyltitanate (Dorf KETAL) and 0.25 ml tetrahydrofuran (from Aldrich) wereintroduced into 50 ml n-hexane. 1.8 ml 1M solution of triethyl aluminiumin n-hexane (Aldrich) was introduced into the hexane. The catalystsystem in hexane was introduced into the reactor. The reaction systemwas heated to 60° C. under stirring and pressured to 23 bar with ethenefor 1 hour. The product was collected in an adjacent vessel afterdepressurising. The yield of 1-butene and initiation time weredetermined.

Example 4b (Comparative). 50 ml 1-butene (from Aldrich) was introducedinto a batch reactor (Parr 300 ml Autoclave Model 4566 Mini Benchtopreactor) at 60° C. and 23 bar pressure of ethene. This temperature andpressure were maintained in the reactor throughout the reaction. 0.25 mltetra-n-butyl titanate (Dorf KETAL) and 0.25 ml tetrahydrofuran(Aldrich) were introduced into 50 ml n-hexane. Tetra-n-butyl titanateand tetrahydrofuran in hexane was introduced into the reactor. 1.8 ml 1Msolution of triethyl aluminium in n-hexane (Aldrich) was introduced intothe reactor. The reaction system was heated to 60° C. under stirring andpressured to 23 bar with ethene for 1 hour. The product was collected inan adjacent vessel after depressurising. The yield of but1-ene and theinitiation time were determined.

TABLE 4 Example Catalyst composition Yield Initiation time 4a Pre-mixedHigh Fast 4b sequential addition Medium Slow

Example 5

Example 5 illustrates the catalyst system comprising a titanate, acatalyst modifer, and a methyl aluminoxane, and its use in a process forthe preparation of an α-olefin from an alkene, in particular preparationof 1-butene from ethene. The results are summarized in Table 5.

Example 5a. The reaction is carried out in a batch reactor (Parr 300 mlAutoclave Model 4566 Mini Benchtop reactor) at 60° C. and 23 bar. Thistemperature and pressure are maintained in the reactor throughout thereaction. 0.25 ml tetra-n-butyl titanate (Dorf KETAL) and 0.25 ml of thecatalyst modifier (Aldrich) are introduced into 50 ml n-hexane(Aldrich). To this is added 1.8 ml 1M solution of triethyl aluminium inn-hexane. The catalyst system in hexane is introduced into the reactor.The reaction system is heated to 60° C. under stirring and pressured to23 bar with ethene for 1 hour. The product is collected in an adjacentvessel after depressurising.

Example 5b. Example 5a was repeated except that 0.25 ml of diphenyletherwas used in place of the silazane.

Example 5c. Example 5a was repeated except that 0.25 ml of fluorobenzenewas used in place of the silazane.

Example 5d (Comparative). Example 5a was repeated except that 0.25 ml oftetrahydrofuran was used in place of the silazane.

TABLE 5 Polymer Example Catalyst modifier Yield Activation time fouling5a ((CH₃)₃Si)₂NH Very high Very short No 5b Ph₂O Very high Very short No5c PhF Very high Very short No 5d Tetrahydrofuran Medium Medium No

Example 6a—Al/Ti Ratio—Activity and Selectivity

It was found that the catalytic activity of a catalyst compositionincluding TNBT as a catalyst and TEAL as a co-catalyst increased whenthe Al/Ti molar ratio was increased, as shown in FIG. 5. The 1-buteneselectivity was unaffected within the margin of error (data not shown).While a higher Al/Ti molar ratio can lead to increased catalyticactivity, it may also result in polymer formation, as shown in FIG. 6.It was found that the cut-off point of the Al/Ti molar ratio was about5, above which, polymer formation was observed, as shown in FIG. 6.

Example 6b—Solvent Effect: The Role of 1-olefins

1-Hexene. The following experiments were conducted in a 300 ml jacketedParr autoclave reactor (Parr Model1 4566). The standard conditions were23 bars ethylene pressure and 60° C. for 1 hour. 1 ml of a catalystsolution that includes 45 vol.% THF and 55 vol % of TNBT where TNBT wasnot pre-treated with an inert solvent, was added to 50 ml of 1-hexene(from Aldrich), and 3.6 ml of TEAL was added prior to introduction intoa batch reactor (e.g., an autoclave). No color change was observed; novisible TNBT activation was observed; and no reaction was observed, asshown in FIG. 7. Repeat experiments came to the same results, whilethere was a significant exotherm (heat release) observed once TEAL wasadded to 1-hexene. Accordingly, the solvent (e.g., olefins) can act as aco-catalyst poison impeding and rendering TEAL unavailable fromactivating the titanium complex.

n-Hexane. 1 ml of a catalytic solution including 45 vol. % THF and 55vol % of TNBT was dissolved in 50 ml n-hexane prepared in a glove boxunder a nitrogen atmosphere. Prior to use, 3.6 ml of 1M TEAL solutionwas added (Al/Ti molar ratio is 3). Then, the mixture ofTNBT/THF/TEAL/n-hexane was added to 25 ml n-hexane. The total ethyleneconsumption after 1 hour was 63.8 g. The induction period was about 3minutes. The catalytic solution was added to the reactor by vacuumsuction. The reactor was then pressurized with ethylene from a 2-literaluminum gas cylinder (e ethylene supply) to reach the desired pressure(23 bars in most experiments). The reaction pressure was controlledusing backpressure regulator, while the ethylene consumption wasmeasured using a balance onto which the gas cylinder was placed. Thereactor was equipped with a thermocouple to measure the temperatureinside the reactor. Temperature, pressure, and ethylene consumption datawere recorded using a data acquisition system. Prior to thecatalyst/solvent injection, the reactor heated to 80° C. under vacuumfor at least two hours under vacuum in order to eliminate all traces ofmoisture. The temperature was controlled by a heating mantle/furnace andcooling coil refrigeration. After terminating the reaction bydepressurization, the product was collected, hydrolyzed with deionizedwater, and analyzed by GC and/or GC/MS. Total ethylene consumption wasmeasured by weight difference of the attached ethylene storage cylinder.

The standard BUCAT catalyst batch tested for ethylene dimerization to1-butene was evaluated under the following standard reaction conditions.

Reaction Temperature 60° C. Ethylene Pressure 23 bar Al/Ti molar ratio 2Ti loading in ZrX₄ 1.5 mmol Reaction Time 1 hour Agitator Speed 600 rpmn-Hexane amount 50 mlThe titanium concentration in standard BUCAT is 7.71 wt. %.

Pre-activation. 2 ml of TEAL and 5 ml of n-hexane were mixed in a smallvial, and then 0.5 ml of a catalytic solution including 45 vol. % THFand 55 vol % of TNBT was added to the mixture of TEAL/n-hexane. Anoticeable color change from clear to dark green was observed. Inaddition, immediate reduction was observed and no exotherm was observed.The mixture of TEAL/n-hexane/THF/TNBT was immediately added to 50 ml of1-hexene. The color of the catalytic solution was changed from darkgreen to yellow. Subsequently, the mixture ofTEAL/n-hexane/THF/TNBT/1-hexene was injected to an autoclave reactor byvacuum suction. Slow but immediate reaction was observed, which showedthat the induction period was shortened, as shown in FIG. 7. The totalethylene consumption after 1 hour was about 28 g, as shown in FIG. 7.The pre-activation procedure (pre-activating TNBT by TEAL in thepresence of n-hexane prior to introducing the catalyst composition to anolefin solvent, e.g., 1-hexene) yielded a controlled catalytic reaction,albeit at reduced activity. In addition, there was no fouling(precipitation of polyethylene) observed.

Example 6c—NMR Investigation of 1-olefins Effect

To better understand the 1-olefins effect, various NMR experiments wereconducted. In the presence of n-hexane, TEAL exists in the dimeric andmonomeric form as AlEt₃ and Al₂Et₆ (see FIG. 3). The equilibrium mainlyshifts towards the dimer. While the smaller trimethylaluminum (TMA)appears only as dimer, the larger the alkyl moiety gets the more theequilibrium shifts towards the monomeric form. In the presence of THF(or 1-hexene), polarity of the solvent increased resulting in asignificant shift of ¹H NMR signal to higher field, i.e., lower chemicalshift (0.4 ppm to -1.0 ppm) forming a monomeric combined with the THF(AlR₃-THF adduct). Similarly, in presence of THF or 1-hexene, conversionof the dimeric into the monomeric form was evidenced by the observedchemical shifts of methyl- and methylene signals, i.e., from 0.3 ppm to-0.7 ppm & 1.0 ppm to 0.9 ppm, respectively.

¹³C NMR studies showed only small differences in the signal pattern,except the variation of the methyl and methylene signal intensity ofTEAL in the presence of THF. This observation supports the conversion ofthe dimeric into the monomeric species.

²⁷Al NMR studies also supported these observations and showed theformation of a 3-coordinated Al-complex (=monomer) as evidenced from theappearance of the ²⁷Al signals at 183.0 ppm in presence of THF for bothTMA and TEAL. On the other hand, the ²⁷Al signals of TEAL/TMA appearedat 156.0 ppm (i.e., dimeric form with 4-coordinated Al-complex) in theabsence of THF.

Consequently, the co-catalyst TEAL remained as a dimer in the presenceof 1-hexene but the catalytic activity accelerates when the co-catalystexists as a monomer. On the other hand, the co-catalyst TEAL/TMAconverts into monomeric form in the presence of THF, thereby activatingthe catalyst.

The invention is further illustrated by the following embodiments.

Embodiment 1

A catalyst composition comprising a titanate of the formula Ti(OR)₄wherein each R is the same or different, and is a hydrocarbon residue; acatalyst additive, wherein the catalyst additive is a dibutyl ether, asilicate, a silazane, an aromatic ether, a fluorocarbon, or acombination comprising at least one of the foregoing; and an organicaluminium compound.

Embodiment 2

The catalyst composition of embodiment 1, wherein the modifier isdi-n-butyl ether.

Embodiment 3

The catalyst composition of embodiment 1, wherein the catalyst additiveis a silicate, preferably a silicate of the formula SiR_(y)(OR)_(4-y),wherein y is 1 to 3, preferably wherein y is 0, and each R is the sameor different and is hydrogen or a C₁₋₁₂ hydrocarbon residue, preferablyC₁-C₆ alkyl group, provided that R is not hydrogen when it is directlybonded to silicon, preferably wherein the silicate is Si(OCH₂CH₃)₄.

Embodiment 4

The catalyst composition of embodiment 1, wherein the modifier is asilazane of the formula (SiR₃)NH(SiR₃), wherein each R is the same ordifferent, and is hydrogen, a hydrocarbon residue, or a halogen,preferably wherein R is a C₁₋₁₂ hydrocarbon residue, preferably a C₁-C₆alkyl group, more preferably wherein each R is methyl.

Embodiment 5

The catalyst composition of embodiment 1, wherein the modifier is anaromatic ether of the formula R¹OR², wherein each R¹ is a hydrocarbonresidue and R² is an aromatic hydrocarbon residue, preferably whereineach R¹ and R² is the same or different substituted or unsubstitutedC₆₋₁₅ aromatic group more preferably wherein each R¹ and R² is the samesubstituted or unsubstituted C₆₋₁₀ aromatic group, wherein each R¹ andR² is phenyl.

Embodiment 6

The catalyst composition of embodiment 5, wherein the modifier is afluoro hydrocarbon, preferably a fluorinated C₁₋₁₅ hydrocarbon,preferably a fluorinated C₆₋₁₂ aromatic hydrocarbon, more preferablyfluorobenzene.

Embodiment 7

The catalyst composition of any one or more of embodiments 1 to 6,further comprising an amine catalyst modifier or an further ethercatalyst modifier distinct from the dibutyl ether and the aromaticether, preferably tetrahydrofuran, preferably wherein the catalystadditive and the further ether catalyst modifier are present in a molarratio about 1:5 to about 5:1.

Embodiment 8

The catalyst composition of any one or more of embodiments 1 to 7,wherein the catalyst composition is dissolved in a hydrocarbon solvent,preferably an alkane solvent, an aromatic solvent, or an alkene solvent,more preferably a C₆-C₁₂ alkane or a C₆-C₁₂ alkene, more preferablybutene, hexane, heptane, octane, or a combination comprising at leastone of the foregoing solvents, most preferably hexane.

Embodiment 9

The catalyst composition of any one or more of embodiments 1 to 8,wherein the catalyst composition comprises a ratio of titanium toaluminum of about 1:1 to about 40:1, preferably about 1:1 to about 1:5.

Embodiment 10

The catalyst composition of any one or more of embodiments 1 to 9,wherein the titanate is Ti(O-butyl)₄, Ti(O-n-alkyl)₄, Ti(O-n-butyl)₄, ora combination comprising at least one of the foregoing; and the organicaluminium compound is of the formula Al_(n)R_(3n), wherein n is 1 or 2and each R is the same or different, and is hydrogen, a hydrocarbonresidue, or halogen, preferably wherein the aluminium compound istriethyl aluminium.

Embodiment 11

A process for the preparation of the catalyst composition of any one ormore of embodiments 1 to 10, comprising pre-treating the titanate andthe catalyst additive with an inert solvent, preferably hexane; andcombining the pre-treated titanate and catalyst additive with theorganic aluminum compound.

Embodiment 12

A reaction process for the preparation of a α-olefin, comprisingcontacting an alkene with the catalyst composition of any one or more ofembodiments 1 to 11 under conditions effective to form the α-olefin.

Embodiment 13

The reaction process according to embodiment 12, wherein the alkene isethene and the α-olefin is 1-butene.

Embodiment 14

The reaction process of any one or more of embodiments 12 to 13, whereinthe reaction process is conducted in a homogenous liquid phasecomprising the α-olefin, preferably wherein the liquid phase comprisesat least about 50 wt. % 1-butene, based on the total weight of theliquid phase.

Embodiment 15

The process of any one or more of embodiments 12 to 14, wherein theconditions comprise at least one of a pressure of about 1 to about 120bar, preferably about 5 to about 50 bar, or a temperature of about 30 toabout 150° C., preferably about 40 to about 80° C.

Embodiment 16

A process for the preparation of a downstream product, the processcomprising reacting the α-olefin prepared according to any one or moreof embodiments 12 to 16, to provide the downstream product, preferablywherein the the downstream product is a homopolymer or copolymercomprising units derived from the α-olefin.

Embodiment 17

The process of embodiment 16, further comprising shaping downstreamproduct to provide an article.

The term “about” or “substantially” means within an acceptable errorrange for the particular value as determined by one of ordinary skill inthe art, which will depend in part on how the value is measured ordetermined, i.e., the limitations of the measurement system. Forexample, “about” can mean a range of up to 20%, up to 10%, up to 5%, andor up to 1% of a given value. The singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.“Or” means “and/or.” Unless defined otherwise, technical and scientificterms used herein have the same meaning as is commonly understood by oneof skill in the art to which this invention belongs. The endpoints ofall ranges directed to the same component or property are inclusive andindependently combinable (e.g., ranges of “less than or equal to 25 wt%, or 5 wt % to 20 wt %,” is inclusive of the endpoints and allintermediate values of the ranges of “5 wt % to 25 wt %,” etc.).Disclosure of a narrower range or more specific group in addition to abroader range is not a disclaimer of the broader range or larger group.

All publications, patents, and patent applications cited herein arehereby expressly incorporated by reference for all purposes to the sameextent as if each was so individually denoted.

Although the presently disclosed subject matter and its advantages havebeen described in detail, it should be understood that various changes,substitutions, and alterations can be made herein without departing fromthe spirit and scope of the presently disclosed subject matter asdefined by the appended claims. Moreover, the scope of the presentlydisclosed subject matter is not intended to be limited to the particularembodiments described in the specification. Accordingly, the appendedclaims are intended to include within their scope such modifications.

What is claimed is:
 1. A catalyst composition comprising a titanate ofthe formula Ti(OR)₄ wherein each R is the same or different, and is ahydrocarbon residue; a catalyst additive, wherein the catalyst additiveis a dibutyl ether, a silicate, a silazane, an aromatic ether, afluorohydrocarbon, or a combination comprising at least one of theforegoing; and an organic aluminium compound.
 2. The catalystcomposition of claim 1, wherein the catalyst additive is di-n-butylether.
 3. The catalyst composition of claim 1, wherein the catalystadditive is a silicate of the formula SiR_(y)(OR)_(4-y), wherein y is 1to 3, and each R is the same or different and is hydrogen or a C₁₋₁₂hydrocarbon residue, provided that R is not hydrogen when it is directlybonded to silicon.
 4. The catalyst composition of claim 1, wherein thecatalyst additive is a silazane of the formula (SiR₃)NH(SiR₃), whereineach R is the same or different, and is hydrogen, a hydrocarbon residue,or a halogen.
 5. The catalyst composition of claim 1, wherein thecatalyst additive is an aromatic ether of the formula R¹OR², whereineach R¹ is a hydrocarbon residue and R² is an aromatic hydrocarbonresidue.
 6. The catalyst composition of claim 1, wherein the catalystadditive is a fluorinated C₁₋₁₅ hydrocarbon.
 7. The catalyst compositionof claim 1, further comprising an amine catalyst modifier or a furtherether catalyst modifier distinct from the dibutyl ether and the aromaticether.
 8. The catalyst composition of claim 1, wherein the catalystcomposition is dissolved in a hydrocarbon solvent.
 9. The catalystcomposition of claim 1, wherein the catalyst composition comprises aratio of titanium to aluminum of about 1:1 to about 40:1. 10.(Previously presented The catalyst composition of claim 1, wherein thetitanate is Ti(O-butyl)₄, Ti(O-n-alkyl)₄, Ti(O-n-butyl)₄, or acombination comprising at least one of the foregoing; and the organicaluminium compound is of the formula Al_(n)R_(3n), wherein n is 1 or 2and each R is the same or different, and is hydrogen, a hydrocarbonresidue, or halogen.
 11. A process for the preparation of the catalystcomposition of claim 1, comprising pre-treating the titanate and thecatalyst additive with an inert solvent; and combining the pre-treatedtitanate and catalyst additive with the organic aluminum compound.
 12. Areaction process for the preparation of an α-olefin, comprisingcontacting an alkene with the catalyst composition of claim 1 underconditions effective to form the α-olefin.
 13. The reaction processaccording to claim 12, wherein the alkene is ethene and the α-olefin is1-butene.
 14. The reaction process of claim 12, wherein the reactionprocess is conducted in a homogenous liquid phase comprising theα-olefin.
 15. The process of claim 12, wherein the conditions compriseat least one of a pressure of about 1 to about 120 bar, or a temperatureof about 30 to about 150° C.
 16. A process for the preparation of adownstream product, the process comprising: reacting the α-olefinprepared according to claim 12, to provide the downstream product,wherein the downstream product is a homopolymer or copolymer comprisingunits derived from the α-olefin.
 17. The process of claim 16, furthercomprising shaping downstream product to provide an article.
 18. Thecatalyst composition of claim 3, wherein the silicate is Si(OCH₂CH₃)₄.19. The catalyst composition of claim 4, wherein R is a C₁₋₁₂hydrocarbon residue.
 20. The catalyst composition of claim 5, whereineach R¹ and R² is the same or different substituted or unsubstitutedC₆₋₁₅ aromatic group.
 21. (canceled)